import java.sql.*;

public class Main {
    public static void main(String[] args) {
        Connection root=null;
        PreparedStatement preparedStatement=null;
        ResultSet resultSet=null;
        //jdbc步骤
        //1.加载驱动
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            root = DriverManager.getConnection(url, "root", "2005");
           /* if(root!=null){
                System.out.println("连接成功");
            }*/

            //3.写sql
            String sql="SELECT * FROM user";
            //4.预编译sql
            preparedStatement = root.prepareStatement(sql);
            //5.执行sql
            resultSet = preparedStatement.executeQuery();
            //6.遍历结果
            while (resultSet.next()){
                int id = resultSet.getInt(1);
                String name= resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println(id+"----"+name+"----"+pass);
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }finally {
            //7.关闭资源  最后创建的最先关闭

            try {
                if(resultSet!=null){
                resultSet.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (root!=null){
                    root.close();
                }

            } catch (SQLException e) {
                throw new RuntimeException(e);
            }


        }
    }

    }
